Threshold temperature of superfluorescence generation in CuCl quantum dots under resonant excitation of excitons and resonant two-photon excitation of biexcitons.

We studied the threshold temperature of superfluorescence (SF) generation with regard to biexcitons in CuCl quantum dots (QDs) under resonant two-photon excitation of biexcitons and resonant excitation of excitons to demonstrate the influence of initial population densities in the QDs on SF generation. As a result, the threshold temperature under the resonant excitation of excitons was higher than that under the two-photon excitation of biexcitons. This indicates that the high density of excited dots facilitates the rapid establishment of coherence among the dots, overcoming disadvantages of incomplete population inversion and formation process of biexcitons. We performed a theoretical calculation of the time profiles of the biexcitonic emission based on semiconductor luminescence equations. The experimentally obtained temperature dependence of the time profiles was qualitatively reproduced by calculating their dependence on the dephasing rate. In addition, we estimated the temperature dependence of the phase relaxation time of the biexcitons in the CuCl QDs by analyzing the temperature dependence of SF.

The skill qualification system for portal hypertension in Japan.

Objectives: The diverse treatments available for portal hypertension require specialized knowledge of hemodynamics and include endoscopic treatments, interventional radiology (IVR), and surgery. The Japan Society for Portal Hypertension has developed the skill qualification system (SQS) for portal hypertension and began examination in 2014. Here, the status and validity of the judgment of the SQS examination were evaluated. Methods: From 2014 to 2020, 79 applicants were evaluated by the SQS for portal hypertension. Each unedited video submitted as a candidate procedure was evaluated by two judges, and a grade of greater than 70% for the scoring items assessed by the judges was required to pass the examination. Inter-rater agreement of success/failure between the two judges was investigated by the AC1 coefficient. Results: The results of two judges differed for 11 of the 79 videos (13.9%), and five applicants (6.3%) ultimately failed the examination. The percentages of total points received by the applicants with endoscopic treatments, IVR, and surgery were 87.3%, 79.4%, and 80.8%, respectively. There were significant differences in the percentages between endoscopic treatments and IVR (P = 0.0015). The AC1 coefficients were 0.84 for the applicants overall, 0.93 for endoscopic treatments, 0.66 for IVR, and 0.72 for surgery. Similarly, there were significant differences in the AC1 coefficient between endoscopic treatments and IVR (P = 0.021). Conclusions: The SQS for portal hypertension of the Japan Society for Portal Hypertension showed high reliability for video assessments by the judges. This system may contribute to the spread and further development of safe and effective treatments for portal hypertension in Japan.

Multiple esophageal hematomas with oozing observed and successfully treated after transcatheter mitral valve edge-to-edge repair procedure.

Although previously reported as relatively rare, esophageal hematoma can likely develop in patients on anticoagulants or those with underlying hemorrhagic disorders. From April 2018 to December 2018, among 36 patients who received transcatheter mitral valve edge-to-edge repair (TMVr) at our hospital, seven (19.4%), who were suspected of having digestive tract hemorrhage evidenced by blood stains on a probe extracted after transesophageal echocardiography, underwent esophagogastroduodenoscopy. Esophageal hematomas were noted in all patients, and endoscopic hemostasis was performed in two cases. Depending on their form, hematomas were noted on the submucosa and the epithelium of the shallow esophageal layer. Esophageal hematomas caused by transesophageal echocardiography for TMVr are not rare, and clinicians should be aware of it.

Comparison of various risk scores for the prognosis of hemorrhagic upper gastrointestinal mucosal disorder.

BACKGROUND: Various risk scores have been proposed that are useful for the management of upper gastrointestinal bleeding (UGIB), which is an important disease in emergency medicine. Few studies have examined the usefulness of Charlson Comorbidity index (CCI) in this disease, which evaluates the patient's general condition by scoring the patient's underlying disease. There have been no studies investigating the efficacy of CCI compared to other risk scores in the management of UGIB requiring endoscopic hemostasis. METHODS: In addition to the Glasgow-Blatchford score, AIMS65 score, and Rockall score, we investigated the efficacy of the outcome prediction obtained by the original CCI and the updated CCI, scored only with respect to the underlying disease. We also examined the cutoff value when using the risk score. This retrospective study included 265 patients with hemorrhagic upper gastrointestinal mucosal lesions who underwent emergency endoscopic hemostasis during a 6-year period between 2011 and 2016 in our hospital. RESULTS: The updated CCI and AIMS65 score correlated with prognosis in multivariate analysis (p = 0.002 and p = 0.003, respectively). In clinical practice, the prognosis might be worse if both updated CCI and AIMS65 score were 3 point or more. CONCLUSION: In addition to the AIMS65 score, the updated CCI can be a useful tool for managing upper gastrointestinal mucosal disorder bleeding that requires endoscopic hemostasis.

Novel surgical approach without bowel resection for multiple gastrointestinal lipomatosis: A case report.

INTRODUCTION: Asymptomatic lipoma only requires observation, whereas symptomatic lipoma requires treatment such as endoscopic or surgical resection. However, in case of multiple lipomas, with evident diffusion and malignancy, resection procedure and range cannot be determined. We experienced GI lipomatosis (multiple lipomas) diffusely existing from the duodenum to the small intestine and involved recurrent intussusception. PRESENTATION OF CASE: 47 year-old female was a history of open bowel resection for intestinal obstruction caused by intussusceptions of multiple small intestinal lipoma 11 years ago. EGD showed duodenal lipoma, and CT showed diffuse multiple lipomas from the proximal jejunum to the distal ileum. Another CT also showed intussusception of small intestine, but no signs of intestinal obstruction. Surgical procedures performed included diagnostic laparoscopy. All intestinal lipomas were resected with local excision, and duodenal lipoma was resected with ESD without any bowel resection. DISCUSSION: Multiple local excision ESD for multiple GI lipomatosis have not been reported. The most problematic thing is that if extensive resection is performed to cut off all multiple lipoma, short bowel syndrome may occur. Determining the range to be cut remains unclear. CONCLUSIONS: Multiple local excision ± ESD seemed to be one of the methods in resecting multiple GI lipomatosis. In the future, cases and indications of surgery and resection method for GI lipoma should be accumulated and considered, respectively.

Visualization of water transport into soybean nodules by Tof-SIMS cryo system.

This paper examined the route of water supply into soybean nodules through the new visualization technique of time of flight secondary ion mass spectrometry (Tof-SIMS) cryo system, and obtained circumstantial evidence for the water inflow route. The maximum resolution of the Tof-SIMS imaging used by this study was 1.8 µm (defined as the three pixel step length), which allowed us to detect water movement at the cellular level. Deuterium-labeled water was supplied to soybean plants for 4h and the presence of deuterium in soybean nodules was analyzed by the Tof-SIMS cryo system. Deuterium ions were found only in the endodermis tissue surrounding the central cylinder in soybean nodules. Neither xylem vessels nor phloem complex itself did not indicate any deuterium accumulation. Deuterium-ion counts in the endodermis tissue were not changed by girdling treatment, which restricted water movement through the phloem complex. The results strongly indicated that nodule tissues did not receive water directly from the phloem complex, but received water through root cortex apoplastic pathway from the root axis.

Oxygen saturation and electromyographic changes in masseter muscle during experimental chewing of gum with harder texture.

OBJECTIVE: The purpose of this study was to clarify the relationship between changes in masseter muscle oxygenation measured by near-infrared spectroscopy (NIRS) and changes in the electromyographic (EMG) power spectrum during experimental chewing of gum with harder texture, to improve the understanding of the use of NIRS in assessing masseter muscle fatigue. MATERIAL AND METHODS: Ten female volunteers with normal occlusion were examined. Mean age (standard deviation) was 28.4 (3.8) years. Mean fracture stress of gum was 12.5 × 10(4) N/m(2). Subjects were instructed to chew gum for 60 s (75 strokes) on the voluntary chewing side at a pace of 1.25 strokes/s. Simultaneous recordings of NIRS and EMG signals from masseter muscle were performed during gum chewing. RESULTS: Oxygen saturation levels decreased from the start of chewing, then stabilized with a break point between the two phases. The normalized EMG amplitude increased and the mean frequency of the EMG power spectrum decreased during gum chewing. The timing of break point appearance was related to the timing of a significant decrease in median frequency, but no clear relationships were found between break point appearance and increased EMG amplitude. CONCLUSIONS: These results suggest that the break point of the oxygen saturation curve, as obtained from NIRS measurements, could be used as an indicator of masseter muscle fatigue as assessed by a shift in the EMG power spectrum to lower frequencies.

Visualization of lateral water transport pathways in soybean by a time of flight-secondary ion mass spectrometry cryo-system.

Water movement between cells in a plant body is the basic phenomenon of plant solute transport; however, it has not been well documented due to limitations in observational techniques. This paper reports a visualization technique to observe water movement among plant cells in different tissues using a time of flight-secondary ion mass spectrometry (Tof-SIMS) cryo-system. The specific purpose of this study is to examine the route of water supply from xylem to stem tissues. The maximum resolution of Tof-SIMS imaging was 1.8 µm (defined as the three pixel step length), which allowed detection of water movement at the cellular level. Deuterium-labelled water was found in xylem vessels in the stem 2.5 min after the uptake of labelled water by soybean plants. The water moved from the xylem to the phloem, cambium, and cortex tissues within 30-60 min after water absorption. Deuterium ion counts in the phloem complex were slightly higher than those in the cortex and cambium tissue seen in enlarged images of stem cell tissue during high transpiration. However, deuterium ion counts in the phloem were lower than those in the cambium at night with no evaporative demand. These results indicate that the stem tissues do not receive water directly from the xylem, but rather from the phloem, during high evaporative demand. In contrast, xylem water would be directly supplied to the growing sink during the night without evaporative demand.

Factors predicting incomplete endoscopic hemostasis in bleeding gastroduodenal ulcers.

BACKGROUND/AIMS: To investigate the factors contributing to failure of initial hemostasis in patients undergoing endoscopic hemostasis. METHODOLOGY: A total of 316 patients underwent endoscopic hemostasis for bleeding peptic ulcers in a period of 4 years. RESULTS: For hemostatic procedures, application of hemostatic clips, band ligation, injection of hypertonic saline epinephrine solution, soft coagulation, and argon plasma coagulation were employed either singly or in combination. Patients were divided into the following 2 groups for multivariate analysis: durable hemostasis (n = 268) and failed initial (incomplete) hemostasis (n = 48). Hemodialysis was a risk factor of incomplete hemostasis (Odds Ratio [OR] = 2.306, 95% confidence interval [CI] = 1.033-5.147; p = 0.041). Compared with the duodenal 2nd portion, the following bleeding sites had significantly lower risk of incomplete hemostasis (approximately 5 times less likely): The duodenal bulb (D), OR = 0.215, 95% CI = 0.058-0.797 (p = 0.022); the L region, OR = 0.207, 95% CI = 0.046-0.919 (p = 0.038); the M region, OR = 0.132, 95% CI = 0.036-0.482 (p = 0.002); and the U region, OR = 0.164, 95% CI = 0.041-0.649 (p = 0.01). CONCLUSIONn: Hemodialysis and a bleeding site located in the duodenal second portion were the factors strongly associated with incomplete hemostasis in bleeding gastroduodenal ulcers.

General rules for recording endoscopic findings of esophagogastric varices (2nd edition).

General rules for recording endoscopic findings of esophageal varices were initially proposed in 1980 and revised in 1991. These rules have widely been used in Japan and other countries. Recently, portal hypertensive gastropathy has been recognized as a distinct histological and functional entity. Endoscopic ultrasonography can clearly depict vascular structures around the esophageal wall in patients with portal hypertension. Owing to progress in medicine, we have updated and slightly modified the former rules. The revised rules are simpler and more straightforward than the former rules and include newly recognized findings of portal hypertensive gastropathy and a new classification for endoscopic ultrasonographic findings.

Analysis of masseter muscle oxygenation and mandibular movement during experimental gum chewing with different hardness.

OBJECTIVE: The purpose of this study was to analyze masseter muscle oxygenation changes and mandibular movements in the experimental chewing of gums with different hardness. MATERIAL AND METHODS: Subjects for this experiment comprised 23 male volunteers with normal occlusion. Mean age (SD) was 28.3 (2.2) years. Three kinds of gum with mean fracture stresses of 3.52 x 10(4) N/m(2) (Gum 1), 5.35 x 10(4) N/m(2) (Gum 2), and 14.0 x 10(4) N/m(2) (Gum 3) were used. The subjects were instructed to chew gum for 80 s (100 strokes) on the voluntary chewing side at a pace of 1.25 strokes/s. Oxygen saturation in the masseter muscle and mandibular movement during gum chewing were recorded simultaneously using near-infrared spectroscopy tissue oximetry and mandibular kinesiography. RESULTS: For Gum 1, no subjects showed any significant changes in oxygen saturation during gum chewing. For Gum 2, 10 subjects showed no significant changes, whereas the other 13 showed significant decreases in oxygen saturation. For Gum 3, significant decreases were seen in all subjects. Chewing motions were larger and velocity was higher in gum chewing with decreases in masseter muscle oxygen saturation compared to chewing showing no significant changes. CONCLUSIONS: The results suggest that the harder texture of gum enlarges chewing motion and increases chewing velocity, with an increase in the contribution of anaerobic metabolism to energy yield in masseter muscle. Differences in the responses to gum hardness may indicate individual differences in muscle fatigue tendencies when chewing harder foods.

Efficacy and safety of omeprazole in Japanese patients with nonerosive reflux disease.

BACKGROUND: There is increasing awareness of nonerosive reflux disease (NERD) as a disease requiring treatment in Japan. This randomized, double-blind, placebo-controlled, parallel-group study was conducted to investigate the efficacy and safety of omeprazole 10 mg and 20 mg once daily in Japanese patients with NERD. METHODS: Patients with heartburn for at least 2 days a week during the month before entry into the study and no endoscopic signs of a mucosal break (grade M or N according to Hoshihara's modification of the Los Angeles classification) were randomly assigned to one of three groups (omeprazole 10 mg or 20 mg, or placebo) once daily for 4 weeks. RESULTS: Overall, 355 patients were enrolled, of whom 284 were randomly assigned to one of the three groups (omeprazole 10 mg, n = 96; omeprazole 20 mg, n = 93; placebo, n = 95). The rate of complete resolution of heartburn in week 4 was significantly higher in patients treated with omeprazole 10 mg [32.3%, 95% confidence interval (CI), 22.9%-41.6%] or 20 mg (25.8%, 95% CI, 16.9%-34.7%) than in the placebo group (12.0%, 95% CI, 5.3%-18.6%). No significant difference between the two omeprazole groups was observed. The rate of complete resolution of heartburn by omeprazole was similar between patients with grade M and those with grade N esophagus. Omeprazole also increased the rate of sufficient relief from heartburn. Omeprazole was well tolerated. CONCLUSIONS: Omeprazole 10 mg or 20 mg once daily is effective and well tolerated in patients with NERD regardless of their endoscopic classification.

Prospective randomized study on the use of a computer-based endoscopic simulator for training in esophagogastroduodenoscopy.

BACKGROUND AND AIM: Computer-based endoscopic simulators have been developed in recent years, and their usefulness has been reported. However, there is no blinded prospective randomized controlled study on esophagogastroduodenoscopy (EGD) training using virtual reality simulators. The present study aimed to assess the effectiveness of a computer-based simulator for basic training in EGD. METHODS: The GI-Mentor II simulator was used. The subjects were 20 hospital medical residents. After receiving an explanation regarding the fundamentals of endoscopy, 10 trainees were each randomized into a simulator group and a non-simulator group. The simulator group received 5 h of training with the GI-Mentor II plus bedside training, while the non-simulator group received bedside training. Subsequently, each subject performed endoscopy twice for assessment. Performance was evaluated according to a five-grade scale for a total of 11 items. RESULTS: The score was significantly higher in the skills required for insertion into the esophagus, passing from the esophagogastric junction (EGJ) to the antrum, passing through the pylorus, and examination of the duodenal bulb and the fornix. CONCLUSIONS: The performance of endoscopy was improved by 5 h of simulator training. The simulator was more effective with regard to the items related to manipulation skills. Computer-based simulator training in EGD is useful for beginners.

The clinical meaning of mucin phenotype and Epstein-Barr virus infection in gastric cancer.

BACKGROUND/AIMS: Differentiated type adenocarcinomas producing gastric type mucin are receiving much attention because of their degree of clinical malignancy. Most Epstein-Barr virus (EBV)-associated gastric cancers are undifferentiated type, and correlate with gastric type mucin. We analyzed the clinical meaning of mucin phenotypes and the detection of EBV in gastric cancers. METHODOLOGY: The objects of study were 120 consecutive gastric cancer lesions, resected endoscopically (EMR group, n=54) or surgically (surgery group, n=66). The mucin phenotypes were determined using immunostaining for human gastric mucin (HGM), MUC2, and CD10. Changes in histological type within the lesions were examined. The presence of EBV was determined using in situ hybridization for EBV-encoded small RNA 1 (EBER-1). RESULTS: The incomplete intestinal phenotype accounted for 83% of the EMR group, and the gastric phenotype for only 13%. None of the EMR group lesions had changes in the degree of differentiation, and there was no EBER-1-positive lesion. In the surgery group, the gastric phenotype accounted for 29%, significantly more than in the EMR group (p=0.0363). The incomplete intestinal phenotype accounted for 64% of surgically resected lesions. Changes in the degree of differentiation were significantly more common in the surgery group (16/66) than in the EMR group (0/54) (p=0.0001), tending to be more common in the gastric phenotype lesions. There were 3 EBER-1-positive lesions in the surgery group, accounting for 5%, and all were HGM positive. CONCLUSIONS: There appears to be little need to determine the mucin phenotype or EBV status of endoscopically resected lesions. In cases of gastric cancer where surgical resection is indicated, however, where the preoperative findings indicate a depth of invasion to SM or greater, and/or an undifferentiated lesion, then mucin phenotyping of biopsy specimens may be useful in predicting the predominant histological type of the tumor.

The long-term efficacy of Helicobacter pylori eradication therapy in patients with idiopathic thrombocytopenic purpura.

BACKGROUND AND AIM: A beneficial effect of Helicobacter pylori (H. pylori) eradication in patients with H. pylori-positive idiopathic thrombocytopenic purpura (ITP) has been reported by several investigators; however, it was not clear whether the recovered platelet count after H. pylori eradication was maintained for a long period. METHOD: Thirty-eight ITP patients who were examined for H. pylori infection were assessed. H. pylori-positive patients received a standard antibiotic therapy for H. pylori eradication. We investigated the long-term effect of H. pylori eradication on platelet recovery in patients with H. pylori-positive ITP. RESULTS: Of the 38 ITP patients, 26 (68.4%) were positive for H. pylori. The response rate of platelet recovery was 56.5% (13/23 patients). Twelve patients showed complete response (CR) and one showed partial response (PR). The mean platelet counts 6 months after eradication significantly increased from 31 x 10(9)/L to 129 x 10(9)/L in 23 H. pylori-eradicated patients (P < 0.001). The median platelet counts of responders 1, 2, 3, and 4 years after eradication were 168 x 10(9)/L (n = 10), 193 x 10(9)/L (n = 9), 168 x 10(9)/L (n = 7), and 243 x 10(9)/L (n = 4) after a mean follow-up of 25.8 months. CONCLUSION: Eradication therapy for H. pylori-positive patients with ITP was effective and a favorable effect was maintained for long periods.

Relationship between molecular markers and endoscopic findings in laterally spreading tumors.

BACKGROUND AND AIM: Characteristic clinicopathological features of laterally spreading tumors (LSTs) have been reported by endoscopists; however, only a few studies have been conducted on the biological features. These studies were not fully associated with the endoscopic findings of LSTs. The aim of this study was to estimate the biological features of each type of endoscopic finding of LST using two molecular markers, matrix metalloproteinase-7 (MMP-7) and beta-catenin. METHODS: Expression of the molecular markers and the endoscopic findings were compared in 22 LSTs and 14 subpedunculated polyps. MMP-7 and beta-catenin were immunostained. Three types of representative endoscopic findings of LST were defined as segments in LSTs. They were 15 granular segments, seven large nodular segments, and seven flat segments that corresponded to the area composed of aggregates of similar size granules, large nodules of diameter more than 10 mm, and a flat surface with no granule, respectively. RESULTS: Expression of MMP-7 and coexpression of MMP-7 and beta-catenin were higher in large nodular segments than in granular segments (P < 0.0167). Among the three types of segments, flat segments showed the highest expression densities of beta-catenin accumulated in the nucleus. Large nodular segments and subpedunculated polyps showed similar expression patterns for the molecular markers. CONCLUSIONS: This study provides new and important information on the relationship between the molecular markers and endoscopic findings of LSTs.

Helicobacter pylori infection prevents nocturnal gastric acid breakthrough.

BACKGROUND/AIMS: Nocturnal gastric acid breakthrough (NAB) is given attention as one of the factors that cause refractory reflux esophagitis. However, its clinical states and mechanisms are not yet clearly understood. We studied whether there will be a NAB outbreak or not among healthy Japanese male volunteers upon administration of omeprazole, as well as what kind of factors will be involved in case of an outbreak. METHODOLOGY: Twenty-one volunteers were selected as subjects for this research. Subjects were checked for symptoms as well as for esophageal hiatal hernia, atrophic patterns and Helicobacter pylori infection of the gastric mucosa. We also conducted esophageal and gastric 24h pH monitoring twice before and after administration of 20mg omeprazole. We further studied CYP2C19 gene polymorphism. RESULTS: We observed NAB outbreak in 9 cases (42.9%) among 21 subjects. All 6 cases (100%) in the H. pylori-positive group showed NAB negative while 6 (40%) of the 15 cases in the H. pylori-negative group showed NAB negative. We found a statistically significant difference between these two groups (P=0.012). We also found a tendency that NAB outbreak is affected by CYP2C19 gene polymorphism. CONCLUSIONS: H. pylori infection prevents NAB among healthy Japanese male volunteers under administration of omeprazole.

Mucin and differentiation in Epstein-Barr virus-associated gastric carcinoma.

BACKGROUND/AIMS: Epstein-Barr virus (EBV) is present in roughly 1 in 10 cases of gastric carcinoma, particularly in undifferentiated adenocarcinomas. To clarify the histological developmental processes in EBV-associated gastric carcinoma, we investigated the presence of EBV infection, changes in the degree of differentiation within lesions, and mucin phenotypes of gastric carcinomas. METHODOLOGY: We had already examined 124 gastric carcinomas using in situ hybridization for EBV-encoded small RNA1 (EBER-1) and 12 lesions were EBER-1-positive. From these lesions we selected 8 carcinomas positive for EBER-1, and then chose 16 EBER-1-negative carcinomas as controls. Hematoxylin and eosin (H&E) stained specimens were examined for changes in histological type within each lesion. Mucin phenotypes of the specimens were determined using human gastric mucin (HGM), MUC2 and CD10 immunostaining. RESULTS: Of the EBER-1-positive lesions, 50% exhibited the gastric type mucin phenotype, whereas only 19% of the EBER-1-negative lesions were of the gastric phenotype. Changes in the histological type were seen within 75% of the EBER-1-positive lesions and within 62.5% of the EBER-1-negative lesions. CONCLUSIONS: The gastric mucin phenotype tended to be more common in the EBV-associated gastric carcinomas. The influence of EBV infection on the change in the histological type within the lesion was considered to be slight.

Endoscopic findings potentially predictive of gastric cancer in borderline lesions diagnosed by forceps biopsy.

BACKGROUND/AIMS: When a benign-malignant borderline lesion is diagnosed by the usual small gastric biopsy, there is sometimes difficulty in making a clinical decision. To clarify potentially useful findings to predict the existence of gastric cancer in borderline lesions diagnosed by forceps biopsy, we retrospectively analyzed endoscopic features. METHODOLOGY: We diagnosed 68 consecutive gastric benign-malignant borderline lesions (57 cases) by forceps biopsy and endoscopically resected them. The final diagnosis for 24 lesions (35.3%) was adenocarcinoma (adenocarcinoma group), and for 40 lesions (58.8%) was adenoma (adenoma group). Comparison with endoscopic findings for the groups was carried out using digitally filed endoscopic photos. RESULTS: We found six endoscopic findings (distal location, reddish surface color, lack of smoothness, lack of glossiness, focal roughness, and focal redness) having statistically significant relationships with adenocarcinoma at the final pathological diagnosis. In multivariate analysis, focal redness (p<0.01) and lack of glossiness (p<0.05) were found to have a significant relationship to gastric cancer. CONCLUSIONS: Endoscopic findings such as focal redness and lack of glossiness were potentially predictive of gastric cancer in borderline lesions diagnosed by forceps biopsy.